1. Field of the Invention
One embodiment of the disclosed invention relates to a silicon on insulator (SOI) substrate and a manufacturing method thereof.
2. Description of the Related Art
In recent years, a silicon on insulator (SOI) substrate that includes a thin single crystal silicon layer on an insulating surface has been developed instead of a bulk silicon wafer.
As an example of a method for manufacturing an SOI substrate, the following method can be given. Hydrogen ions are added to a single crystal silicon substrate so that an embrittlement layer (also referred to as a separation layer) is formed. A base substrate (for example a glass substrate) and the single crystal silicon substrate are bonded to each other. The bonded single crystal silicon substrate is heated so that a thin single crystal layer is separated along the embrittlement layer; accordingly, a thin single crystal layer is formed over the base substrate (see Patent Documents 1 to 4).